The present invention relates to a package for an electronic device, and more particularly to a package having such a structure with outerleads wherein at least a final layer is electroplated on the outerleads prior to glass-sealing.
Cer-dip type ceramic packages are widely used for electronic devices because of their lower production costs compared to multilayered ceramic type packages.
Cer-dip type ceramic packages have outer leads that are usually electroplated with tin or an alloy of tin and lead after sealing the package by means of fused glass. Such cer-dip type ceramic packages can be successfully assembled on a substrate by soldering. The outerleads, however, are liable to incompletely contact gold-electroplated sockets due to fretting corrosion. To prevent this, gold is often electroplated on the outerlead area.
Gold-electroplating after glass-sealing, however, results in several disadvantages. The sealing glass is chemically etched by the gold-electroplating bath. The surface of etched glass is chemically active and tends to be electroplated, even partly, with gold, which leads to an electric short-circuit between the outerleads. The glass dissolved by the etching, further, contaminates the electroplating bath and shortens its service life.